Evaluation of Soybean Genotypes (Glycine max and Glycine soja) for Resistance to the Root-Knot Nematode, Meloidogyne enterolobii

Abstract

Potential resistance to the root-knot nematode, Meloidogyne enterolobii, in 72 Glycine soja and 44 Glycine max soybean genotypes was evaluated in greenhouse experiments. Approximately 2,500 eggs of M. enterolobii were inoculated on each soybean genotype grown in a steam sterilized 1:1 sand to soil mixture. Sixty days post inoculation, plants were destructively harvested to determine the host status. The host status of each soybean genotype was determined by assessing root galling severity and calculating the final eggs per root system divided by the initial inoculum, or the reproduction factor (Rf). Five G. soja soybean genotypes were identified as resistant (Rf < 1) to M. enterolobii: ‘407202’, ‘407239’, ‘424083’, ‘507618’, and ‘639621’. None of the tested G. max soybean genotypes were identified as resistant to M. enterolobii. Some of the G. max genotypes determined to be susceptible to M. enterolobii include ‘Hagood’, ‘Avery’, ‘Rhodes’, ‘Santee’ and ‘Bryan’. The genotype ‘Bryan’ had the lowest Rf values among the group at 5.06 and 6.67 in two independent trials respectively, which represents a 5- to 6-fold increase in reproduction of M. enterolobii. Plant genotypes resistant to root-knot nematodes are effective in managing the disease and preserving yield, are cost-efficient, and environmentally sustainable, and host resistance is often regarded as the most robust management tactic for controlling plant parasitic nematodes. Resistance to root-knot nematodes in soybean genotypes has been identified for other Meloidogyne species, yet there is currently limited data regarding soybean host status to the highly aggressive nematode, M. enterolobii. This study adds to knowledge of potential native resistance to M. enterolobii in wild and cultivated soybean.